perf(copy): run filter in parallel as well

lib/copy/copy.js

@@ -7,7 +7,7 @@ const { pathExists } = require('../path-exists')
 const { utimesMillis } = require('../util/utimes')
 const stat = require('../util/stat')
 
-async function copy (src, dest, opts = {}) {
+async function copy(src, dest, opts = {}) {
   if (typeof opts === 'function') {
     opts = { filter: opts }
   }
@@ -42,12 +42,12 @@ async function copy (src, dest, opts = {}) {
   await getStatsAndPerformCopy(destStat, src, dest, opts)
 }
 
-async function runFilter (src, dest, opts) {
+async function runFilter(src, dest, opts) {
   if (!opts.filter) return true
   return opts.filter(src, dest)
 }
 
-async function getStatsAndPerformCopy (destStat, src, dest, opts) {
+async function getStatsAndPerformCopy(destStat, src, dest, opts) {
   const statFn = opts.dereference ? fs.stat : fs.lstat
   const srcStat = await statFn(src)
 
@@ -65,7 +65,7 @@ async function getStatsAndPerformCopy (destStat, src, dest, opts) {
   throw new Error(`Unknown file: ${src}`)
 }
 
-async function onFile (srcStat, destStat, src, dest, opts) {
+async function onFile(srcStat, destStat, src, dest, opts) {
   if (!destStat) return copyFile(srcStat, src, dest, opts)
 
   if (opts.overwrite) {
@@ -77,7 +77,7 @@ async function onFile (srcStat, destStat, src, dest, opts) {
   }
 }
 
-async function copyFile (srcStat, src, dest, opts) {
+async function copyFile(srcStat, src, dest, opts) {
   await fs.copyFile(src, dest)
   if (opts.preserveTimestamps) {
     // Make sure the file is writable before setting the timestamp
@@ -99,15 +99,15 @@ async function copyFile (srcStat, src, dest, opts) {
   return fs.chmod(dest, srcStat.mode)
 }
 
-function fileIsNotWritable (srcMode) {
+function fileIsNotWritable(srcMode) {
   return (srcMode & 0o200) === 0
 }
 
-function makeFileWritable (dest, srcMode) {
+function makeFileWritable(dest, srcMode) {
   return fs.chmod(dest, srcMode | 0o200)
 }
 
-async function onDir (srcStat, destStat, src, dest, opts) {
+async function onDir(srcStat, destStat, src, dest, opts) {
   // the dest directory might not exist, create it
   if (!destStat) {
     await fs.mkdir(dest)
@@ -120,15 +120,16 @@ async function onDir (srcStat, destStat, src, dest, opts) {
     const srcItem = path.join(src, item.name)
     const destItem = path.join(dest, item.name)
 
-    // skip the item if it is matches by the filter function
-    const include = await runFilter(srcItem, destItem, opts)
-    if (!include) continue
-
     promises.push(
-      stat.checkPaths(srcItem, destItem, 'copy', opts).then(({ destStat }) => {
-        // If the item is a copyable file, `getStatsAndPerformCopy` will copy it
-        // If the item is a directory, `getStatsAndPerformCopy` will call `onDir` recursively
-        return getStatsAndPerformCopy(destStat, srcItem, destItem, opts)
+      runFilter(srcItem, destItem, opts).then(include => {
+        if (include) {
+          // only copy the item if it matches the filter function
+          return stat.checkPaths(srcItem, destItem, 'copy', opts).then(({ destStat }) => {
+            // If the item is a copyable file, `getStatsAndPerformCopy` will copy it
+            // If the item is a directory, `getStatsAndPerformCopy` will call `onDir` recursively
+            return getStatsAndPerformCopy(destStat, srcItem, destItem, opts)
+          })
+        }
       })
     )
   }
@@ -140,7 +141,7 @@ async function onDir (srcStat, destStat, src, dest, opts) {
   }
 }
 
-async function onLink (destStat, src, dest, opts) {
+async function onLink(destStat, src, dest, opts) {
   let resolvedSrc = await fs.readlink(src)
   if (opts.dereference) {
     resolvedSrc = path.resolve(process.cwd(), resolvedSrc)